Breast Asymmetry And Cancer Women Researchers examined the mammograms of 252 women who later developed breast cancer and 252 women of the same age who did not develop the disease.Result: Those who developed breast cancer had higher breast volume asymmetry (difference in volume between left and right breasts) than other women.Theory: Estrogen, which has been linked to breast cancer, may also play a role in breast asymmetry. Want to Keep Reading? Continue reading with a Health Confidential membership. Sign up now Already have an account? Sign in